The Angostura 7yr Dark rum (formerly part of the "butterfly" collection and named for Trinidad's 8,000 member butterfly collection) is aged for a minimum of 7 but as many as 10yrs. After filtering through charcoal, it is given a further maturing. Angostura recommends that it rest in a glass before being sipped neat.
Angostura is a large company with a wide range of products. They're, perhaps, most famous for their bitters--an aromatic that is featured in many recipes including the famous and exquisite Manhattan. They also carry a line of rums (as well as owning a series of scotch and cognac labels.
Angostura rums are distilled in Trinidad from molasses. Trinidad Distillers themselves make other labels of rum, including the ubiquitous Bacardi.